<template>
  <div id="app">
    <router-view/>
  </div>
</template>
<script>

  export default {
    data() {
      return {}
    },
    created() {
      //在页面加载时读取sessionStorage里的状态信息
      if (sessionStorage.getItem('state')) {
        this.$store.replaceState(Object.assign({}, this.$store.state,
          JSON.parse(sessionStorage.getItem('state'))))
      }
      //页面刷新时将state数据存储到sessionStorage中
      window.addEventListener('beforeunload', () => {
        sessionStorage.setItem('state', JSON.stringify(this.$store.state))
      })
    }
  }
</script>
<style lang="less">

</style>
